1. Field of the Invention
The present invention relates to adaptive optics and more particularly to micro-electromechanical systems (MEMS) and nanolaminates for implementing adaptive optics.
2. Description of Related Art
Deformable mirrors in the field of adaptive optics are directed to the improvement of optical signals using information about signal distortions introduced by, for example, the environment in which the optical signals propagate. Several varieties of deformable mirrors have been previously demonstrated. Early deformable mirrors utilized glass or metal plates deformed by piezo or electromagnetic actuators. Later the field of micromechanical systems (e.g., MEMS) was applied to the creation of deformable mirrors. MEMS technology allowed the pixel density to greatly increase with as many as a thousand individual moving mirrors in a single small device. The batch fabrication of such devices decreased the pixel cost by more than a factor of twenty from glass mirrors.
MEMS devices can achieve very accurate deformations because their electrostatic actuators are easy to characterize and are very repeatable. While such devices can create high spatial frequency shapes because the springs internal to the MEMS actuators limit the influence an actuated pixel can have on its not-actuated neighbor, these devices tend to have surface topography limitations and incorporate a limited range of optical materials. Moreover, although they can very accurately position mirrors, these devices have been limited in size and mirror quality. Meanwhile, microfabrication techniques have also been applied to higher quality mirrors by fabricating piezo actuators or electrostatic pads directly on the back of the mirror. These devices, however, are limited in the shapes they can create because each individual actuator affects all of its neighbors.
Accordingly, a need exists for a deformable mirror configuration having greater actuator density than has previously been available for continuous deformable mirrors, and a much higher quality mirror than has previously been available using high-density MEMS deformable mirror configurations. The present invention is directed to such a need.